Yes, people who misuse disabled placards for free parking exist. However, just because a driver appears frisky or fit is not evidence of him being a scofflaw.
I have a placard and am thankful for it. If my walk from the car to my destination is a block or so, my stenosis pain often kicks in; sometimes it is moderate, and other times awful enough to cause me to find a place to sit for a few moments. If I can't find a place to sit, I just tough it out.
I have had surgery to correct the problem and look forward to giving up the placard.